Hydraulic pump control apparatus for construction equipment and control method thereof

Abstract

A hydraulic pump control apparatus for construction equipment includes a first hydraulic pump; a first hydraulic actuator driven by the hydraulic oil of the first hydraulic pump; a first control valve installed on the fluid channel of the first hydraulic pump; a second hydraulic pump connected, to a power take-off apparatus of an engine; a second hydraulic actuator driven by the hydraulic oil of the second hydraulic pump; a second control valve installed on the fluid channel of the second hydraulic pump; a pressure sensor that detects the pressure of the second hydraulic pump; a regulator that controls the amount of oil discharged from the first hydraulic pump; and a controller that computes a horse power value using the detected pressure value of the second hydraulic pump and the amount of oil discharged from the second hydraulic pump and inputs a control signal to the regulator to discharge an amount of oil that corresponds to the difference between the maximum working horse power value of the engine and the computed horse power value of the second hydraulic pump.

1 . A hydraulic pump control apparatus for construction machine comprising;
 a first variable displacement hydraulic pump connected to an engine;
 a first hydraulic actuator driven by, the hydraulic fluid of the first hydraulic pump; 
 a first control valve that is installed in a flow path of the first hydraulic pump, and controls the hydraulic fluid supplied to the first hydraulic actuator; 
 at least one of second hydraulic pumps connected to a power take-off (PTO) apparatus of the engine; 
 a second hydraulic actuator driven by the hydraulic fluid of the second hydraulic pump; 
 a second control valve that is installed in a flow path of the second hydraulic pump, and controls the hydraulic fluid supplied to the second hydraulic actuator; 
 a pressure sensor that is installed in the flow path of the second hydraulic pump, and detects a hydraulic pressure of the second hydraulic pump; 
 a regulator for adjusting a swash plate swivel angle of the first hydraulic pump in order to control a discharge flow rate of the first hydraulic pump; and, 
 a controller that inputs a control signal to the regulator so as to control the first hydraulic pump discharge flow rate corresponding to a difference between the maximum horse power available of the engine and the second hydraulic pump horse power which is calculated using the detected hydraulic pressure and a discharge flow rate of the second hydraulic pump. 
   
     
     
         2 . The hydraulic pump control apparatus for construction machine of  claim 1 , further comprising an engine RPM detection apparatus for detecting engine RPM and inputting the detected signal to a controller, wherein the controller compares the detected engine RPM with a rated RPM, and if the detected RPM is less than the rated RPM, a control signal from the controller is inputted to the regulator so as to reduce the discharge flow rate of the first hydraulic pump. 
     
     
         3 . A control method of a hydraulic pump for construction machine, including a first hydraulic pump connected to an engine; a first hydraulic actuator driven by the hydraulic fluid of the first hydraulic pump; a second hydraulic pump connected to a power take-off (PTO) apparatus of the engine; a second hydraulic actuator driven by the hydraulic fluid of the second hydraulic pump; a pressure sensor that is installed in a flow path of the second hydraulic pump; a regulator for adjusting a swash plate swivel angle of the first hydraulic pump; and a controller to which a detected pressure signal from the pressure sensor is inputted, the method comprising;
 calculating a horse power of the second hydraulic pump using the detected pressure and a discharge flow rate of the second hydraulic pump;   a step of comparing the calculated horse power of the second hydraulic pump with an available horse power;   calculating a first discharge flow rate of the first hydraulic pump based on the ratio of the sum of the basic horse power of the first hydraulic pump and the available horse power to the load pressure of the first hydraulic pump, if the calculated horse power of the second hydraulic pump is less than the available horse power;   calculating a second discharge flow rate of the first hydraulic pump based on the ratio of the basic horse power of the first hydraulic pump to the load pressure of the first hydraulic pump, if the calculated horse power of the second hydraulic pump is greater than the available horse power; and,   inputting a control signal to the regulator so as to discharge the first and second calculated discharge flow rates of the first hydraulic pump.